Crystal fields in the valence-unstable CeNi-based compounds

The influence of a partial delocalization of cerium 4f electrons on the crystalline electric field (CEF) effects measured on Pr paramagnetic impurity ions have been investigated for the series of (Pr, Ce)x(La, Y)1-xNi compounds, which undergo the transition from the intermediate valence (IV) to Kondo state due to the chemical substitution. In the Kondo state the hybridization of cerium 4f electrons and conduction electrons results only in the simultaneous increase of all CEF parameters, while in the IV regime the partial delocalization of cerium 4f electrons is responsible for a charge redistribution that manifests itself in different scales of changes for different CEF parameters. (orig.)